Due to his fighting a war against the Scarlet Crusade, the Argent Dawn, the Forsaken and the Humans of the Alliance, as well as constant incursions of adventurers from every race and nation into the Scourge-controlled Plaguelands on a daily basis, the forces of Kel'Thuzad have been severely taxed to maintain the security of the necropolis. But now the gates of Naxxramas are open, and Kel'Thuzad's new forces are rapidly sweeping away all opposition to the Scourge.

After the defeat of Kel'Thuzad in the Eastern Plaguelands, Naxxramas has returned to Northrend and now hovers above the Carrion Fields in eastern Dragonblight, where it lays siege to the Alliance stronghold of Wintergarde Keep.

A wing of strange fungus, ghouls, gargoyles, maggots and other plagued monstrosities.

This wing has three bosses and is only very slightly more difficult than the Arachnid Quarter, with Noth the Plaguebringer being arguably the easiest boss in the instance. The trash clear to Noth the Plaguebringer and Heigan the Unclean is of medium length with Loatheb having a short gauntlet of quickly respawning maggots and eye stalks rather than a trash clear.

This wing also has three bosses and requires slightly more coordination than the Arachnid or Plague wings, but has no higher gear requirements. The trash clear to Instructor Razuvious is the longest in the instance, with considerable trash clears for Gothik the Harvester and The Four Horsemen.

This quarter contains four bosses and requires slightly higher gear and coordination than the first three wings.

It is recommended new groups tackle this quarter last. Patchwerk is a considerable healer test on Heroic difficulty and Thaddius is a considerable DPS check on Heroic difficulty. The trash clear to Patchwerk is long but Grobbulus and Thaddius have short clears. Gluth has no trash whatsoever.

The Frozen Heart of Naxxramas which contains the two bosses, Sapphiron and Kel'Thuzad, and can be accessed by teleportation orbs.

Pre-Patch 3.3.0 you had to clear each of the four final bosses in the four wings.

Neither boss has any trash to clear.

Sapphiron will severely test the healers of new groups. Kel'Thuzad is considerably easier on 10-man difficulty but is arguably the hardest boss in the instance on Heroic difficulty and will require top effort from all of the raid.

Naxxramas loot includes the Tier 7 raid sets, which are based on the Tier 3 raid sets that dropped in the original Naxxramas. There are two versions: The Tier 7 "Heroes'" sets from the normal mode 10-man, and the Tier 7.5 "Valorous" sets from the heroic mode 25-man. While these sets are inspired by the original Tier 3 sets, they have received significant model updates.[3]

0400Patch 4.0.3 (15-Nov-2010): Any dungeons that previously dropped any type of emblems, will now award Justice Points instead.

0300Patch 3.3.0 (08-Dec-2009): Players no longer need to kill the final bosses in all four wings of this dungeon in order to teleport to Sapphiron. Teleportation orbs have been added to allow players access back and forth from Sapphiron's lair.